<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title></title>
<script type="text/javascript">
//	如果实参个数多于形参个数,那么多余的参数会被忽略,不会有任何错误.
//	如果实参个数少于形参个数,那么没有对应值的形参默认值就是undefined
	function chengji(x,y,z){
		var re = x*y*z;
		alert(re);
	}
	
//	NaN  Not a Number
//	chengji(5,6,7,8,9);
	chengji(5,6);
	
</script>
	</head>
	<body>
	</body>
</html>
